An image projection apparatus, which projects content for presentations or other purposes on a projection screen, may be connected to an image transfer apparatus, for example, a personal computer. An image transfer apparatus of related art generates display image data by regarding the display screen of a display device as a unit and uses the generated display image data to display an image on the display device. Therefore, when an image projection apparatus is used to display the image displayed on the display device, the display image data may be transferred to the image projection apparatus. As such, it may be difficult to satisfy a need to display part of the content on the display screen, for example, only the content that a presenter is presenting.
In contrast to the above method, there is a technique in which a mouse pointer may be used to select any of a plurality of windows displayed on a display device and window data of the selected window may be outputted to an external monitor, as referred to in Japanese Patent Publication No. JP-A-2000-339130.
However, when a plurality of image projection apparatus are connected to an image transfer apparatus, multiple sets of content displayed on the display device may not be transferred to respective desired image projection apparatus. Further, for the content part of which is displayed on the display device, the entire content may not be projected through an image projection apparatus.
The challenges described above may not be limited to an image transfer apparatus to which a plurality of image projection apparatus are connected, but common to an image transfer apparatus to which a plurality of external display devices are connected.